In preparation for an emergency state such as a disaster, a wireless communication system provides a service for notifying that a user is in an emergency state. For example, the wireless communication system provides an emergency call service for transmitting, when a user is in an emergency state, an emergency signal to request the assistance of relevant agencies or other users.
However, a Base Station (BS) may malfunction due to disasters such as earthquakes, fires, and terrors. In this case, a cell area of the BS may collapse, and Mobile Stations (MSs) in the collapsed cell area may be disconnected from the BS to fail to receive the emergency call service.
What is therefore required is a scheme for supporting an emergency call service for MSs that are disconnected from a BS due to the collapse of a cell area of the BS.